1. Field of the invention
The present invention relates to an improved wiper actuating mechanism particularly adapted for use in an oil pressure actuated gauge. It is additionally equipped with an auxiliary spring plate, a pair of wipers, a push rod guide piece and a diaphram board with vertical flange along the periphery thereof so that the operational accuracy of an oil gauge can be effectively advanced.
2. Description of the prior art
In the prior art actuating mechanism as shown in FIG. 1, there are only basic elements provided to actuate a wiper 18A that include a diaphram board 10A having a corrugated cross section, a rubber seal 4A, a push rod 12A, an upper cap 1A and a lower case 2A. The lower case 2A has a central opening for the location of the push rod 12A which is disposed in abutment with the diaphram board 10A and slidably moves up and down in response to the variation of the oil pressure delivered via a pore 40A of a bolt 45A secured to the upper cap 1A. To prevent high pressure oil from leaking from the actuating mechanism housed in between the upper cap 1A and the lower case 2A, the rubber seal 4A is disposed in sealing engagement with the round diaphram board 10A having a flat periphery.
In the above cited prior art, the rubber seal 4A is not restrained by the diaphram board 10A so that it can be deformed into irregular shape in assembly and will have bad effect on the operation of the diaphram board 10A.
Furthermore, the prior art push rod 12A is not limited by any guide piece and is welded to the diaphram board 10A by way of a connection pin. The push rod 12A can be easily offset a little bit when the diaphram 10A is not evenly actuated, causing the wiper 18A to pivot in a less accurate manner.
The one piece wiper 18A is mounted onto a spring biased pivot mount 20A and is in pivotal conductive contact with a -shaped winding board. An adjustable actuation pin 25A secured to the pivot mount 20A is in abutment with a point adjacent to the top periphery of the push rod so that the up and down movement causes the spring biased pivot mount and the wiper to pivot according to the distance of the motion of the push rod actuated by the diaphram driven by oil pressure. The single wiper 18A can easily go out of contact with the winding board 3A periodically due to the vibration of of a vehicle.
Moreover, the wiper can pivot in either direction in accordance with the up or down vibration of the diaphram board 10A and the outcomes of measurement in such cases are slightly different, and the error can be as much as 0.04-0.05 mm, as shown in FIG. 8.